1. Field of the Invention
The present invention relates to an information-processing apparatus configured to implement an interaction between a virtual space and a user who observes the virtual space and to an information-processing method therefor.
2. Description of the Related Art
As is publicly known, a virtual reality system (VR system) refers to a system that performs the following operations. That is, the VR system configures a virtual space using three-dimensional computer graphics (CG) and displays an image in the virtual space on a large-sized display, a mobile apparatus display, or a head-mounted display (HMD). Thus, the VR system can cause a user to feel as if the virtual space is a real space.
In addition, a mixed reality system (MR system) has been developed for superposedly displaying a virtual object generated using three-dimensional CG on an image in a real space. The MR system uses an image in a real space to allow a user to more easily enjoy a sense of actual size than that offered in a conventional VR system. In the case of using an HMD in such a conventional system, a user can feel a greater sense of immersion into a virtual space because the virtual space is displayed according to a viewpoint of the user and a direction of a line of sight (visual axis) of the user.
Meanwhile, in recent years, a method of designing a product using a three-dimensional computer-aided design (3D-CAD) technique has become the mainstream in the field of product design and manufacture. In this regard, as a method for evaluating an object that has been designed with 3D-CAD, a method is generally used for visually evaluating data generated with 3D-CAD and displayed on a screen of a computer as a 3D-CG image.
In addition, a method is also generally used for evaluating a simplified prototype (simplified mock-up) manufactured with a rapid prototyping apparatus and evaluating the prototype based on a tactile sense. However, in the case of evaluating an automobile or a large-sized apparatus with a conventional method, it is not easy to perform a close evaluation because a sense of actual size cannot be obtained on a screen of a computer.
Furthermore, in the case of manufacturing a simplified mock-up, if the size of the mock-up to be manufactured is large, the cost of manufacture may become high. In this regard, a conventional method allows a user to evaluate a product under an environment in which the user can feel a sense of actual size or immersion by displaying CG information with 3D-CAD using the VR system or the MR system.
Thus, the user can more intuitively evaluate or verify a product by looking at a virtual object with an actual size.
In the case of evaluating an operability or assemblability of an object to be designed, not only visual information provided as CG information but also tactile sense information obtained at the time of touching an object are required.
In the case of performing an evaluation of a product to be designed using a mock-up, the user can actually touch and verify the mock-up. However, in order to obtain tactile sense information in the case of using a VR system or an MR system, it is necessary to user a specific apparatus, device, or method.
That is, in order to express a feel of a virtual object expressed with CG information, it is necessary to use a device that performs contact detection processing for detecting a contact of a user with a virtual object and expresses and provides tactile sense information to the user.
A device that expresses tactile sense information is generally called a “haptic device” or a “haptic display”. Such a “haptic device” or a “haptic display” includes a force feedback providing apparatus that expresses a reaction from a virtual object and a cutaneous sense providing apparatus (tactile display) that provides a stimulation to a cutaneous sense of a user.
It is useful to express a reaction from an object using a force feedback providing apparatus to evaluate and verify a product (object) to be designed. However, a conventional force feedback providing apparatus is generally large-sized and thus cannot be easily transported. Accordingly, in the case of virtually evaluating an automobile or a large-sized apparatus, an available scope of evaluating an object to be designed may be restricted because of the poor portability of the force feedback providing apparatus. Thus, in this case, it may become difficult for the user to intuitively perform the necessary evaluation operation.
Furthermore, in the case of using a force feedback providing apparatus over a large area, it is difficult for the user to feel a sense of immersion over the user's body by a tactile sense because only one force point is available to express a feel of the object in most cases. Accordingly, the scope or area of a virtual object available for verification with a tactile sense may be restricted even in the case where the virtual object to be designed is expressed in a VR system or an MR system that can provide a sense of an actual size. Thus, an effect of evaluating an object to be designed with a virtual object of an actual size may be reduced.
On the other hand, in the case of using a small-sized cutaneous sense providing apparatus whose portability is high, the tactile sense can be expressed with a greater sense of immersion by mounting the small-sized cutaneous sense providing apparatus at a plurality of regions of the user's body.
In this regard, as a highly portable cutaneous sense providing apparatus, Patent Cooperation Treaty (PCT) Japanese Translation Patent Application Laid-Open No. 2000-501033 discusses a device that provides a vibration stimulation to a user via a vibration motor mounted at a finger portion of a glove that the user wears according to user's contact with a virtual object.
Furthermore, Japanese Patent Application Laid-Open No. 2003-316493 discusses a method for providing a user with a skin stimulation to the front surface of a finger of a user according to user's contact with a virtual object by using a mechanism for providing a stimulation by pressing against the front surface of the finger of the user, which is disposed at a finger front surface portion of a glove. In the case of expressing a tactile sense using a vibration motor, whether the virtual object has been contacting a region of the user can be expressed although it is difficult to express a reaction force from the virtual object.
Furthermore, such a vibration motor is small-sized, lightweight, and relatively inexpensive, and can generate a stimulation intense enough to cause a user to recognize vibration. Accordingly, a conventional method implements a tactile sense presentation with a greater sense of immersion by using a plurality of vibration motors mounted on the whole body of a user including regions such as fingers or palms.
For example, “Hiroaki Yano, Tetsuro Ogi, Michitaka Hirose: Development of Haptic Suit for Whole Human Body Using Vibrators”, Journal of Virtual Reality Society of Japan, Vol. 3, No. 3, 1998 discusses a device that allows a user wearing twelve vibration motors to recognize a virtual wall at the time of contacting the virtual wall. In the case of using the device discussed therein, twelve vibration motors are mounted on human body regions at the head, the backs of the hand, the elbows, regions around the waist (three pieces), knees, and ankles. The positions of mounting the vibration motors are determined based on a human perception diagram.
Furthermore, “Jonghyun Ryu, Gerard Jounghyun Kim: “Using a Vibro-tactile Display for Enhanced Collision Perception and Presence”, VRST '04, Nov. 10-12, 2004, Hong Kong” discusses a method in which vibration motors are mounted on the body of a user at four positions on the arms and legs, respectively, to provide different information indicating virtual contacts with objects of different feels by varying the vibration of the vibration motors.
Meanwhile, a user may consciously or unconsciously contact a virtual object. In the case of conscious contact, the user can easily recognize the contact even if the intensity of the stimulation provided by a vibration motor is low. On the other hand, in the case of unconscious contact, the user may not even recognize the stimulation provided by a vibration motor if the intensity of the stimulation on a region that has unconsciously contacted the virtual object is not high enough. In particular, in order to express contact of a virtual object on the whole body of a user, the expression of the contact is performed with respect to many regions of the body of the user. Accordingly, in this case, it is difficult for the user to always recognize contact with a virtual object for the whole body.
In this regard, if the user performs an operation with the hands, the user may particularly aware of the hands and thus becomes less aware of the legs. Accordingly, even if a stimulation is provided with respect to contact with a virtual object by the legs, the user may not positively recognize the stimulation.
On the other hand, if the intensity of stimulation is uniformly increased regardless of whether the user is aware of contact so that the user surely receives the provided stimulation information from any position of contact of the user's body with a virtual object, the intensity of stimulation may become very high in the case where the user consciously contacts the virtual object, and thus the user may feel uncomfortable with the excessive stimulation.
As described above, the conventional method cannot solve the above-described problem because it cannot appropriately adjust the intensity of stimulation to be provided according to contact of a user with a virtual object based on whether the user is aware of the contact.